The present invention relates to an electric power source device, and more particularly to an electric power source device for use in a motor vehicle, such as an automotive vehicle, for start-up of an engine associated with such a vehicle.
Automotive vehicles employ, as an electric power source device, a battery for start-up of an associated engine. Upon start-up of an engine at very cold temperatures such as when an automotive vehicle is used under arctic weather conditions, it is required that a battery produce a large electric power for maintaining satisfactory start-up performance of the engine. However, there is a limit for a battery to maintain a sufficiently large capacity under very cold temperatures because the battery uses chemical reaction to produce electric energy and thus a drop in temperature causes a drop in capacity of the battery. A drop in capacity of a battery is caused also by an excessively high temperature which is often experienced when an automotive vehicle is left for a long time at a parking lot under strong sun rays during summer season.
The present invention provides an electric power source device which has eliminated the above mentioned problem encountered in the prior art.